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991.
Byeongmoon Jeong You Han Bae Sung Wan Kim 《Colloids and surfaces. B, Biointerfaces》1999,16(1-4):185-193
Micellization of poly(ethylene glycol-b-(DL-lactic acid-co-glycolic acid)-b-ethylene glycol), PEG-PLGA-PEG, triblock copolymers in water was studied by 13C-NMR (nuclear magnetic resonance), dye solubilization method, and light scattering. Critical micelle concentration was decreased by half by increasing temperature from 20 to 50°C. Enthalpy of micellization was calculated to be 10–20 KJ/mole. Apparent aggregation number, diameter of a micelle abruptly increased while second viral coefficient decreased at ≈30°C suggesting that micellar growth as well as an increase in polymer–polymer attraction occur at this temperature. These findings might suggest that the sol to gel transition at high concentration of aqueous solutions of this polymer is driven by conformational changes of micelles. 相似文献
992.
KWON Sung Duk 《声学学报:英文版》2010,29(1):56-64
Generalized Lamb surface waves are generated in a surface region when ultrasonic waves are incident to the layered substrates such as painted specimen in liquid. Then, backward radiated waves are returned to the direction of incidence by scattering and energy radiation of the surface waves. Hence, the backward radiation could be used in assessing the interracial state between layer and substrate because the surface wave is sensitive to the change of physical properties in a surface region. Painting surface treatment of commercial products and articles occasionally hide the surface region trouble such as roughness and crack. The evaluation of interfacial state under painting layer is very important in the prevention of great accidence, hence the evaluation technique should be nondestructive, fast and easy applicable to the fields. The backward radiations were measured for the painted glass with periodic interfacial roughness immersed in water tank. The effect of interfacial roughness on the angular pattern and frequency spectrum of the ultrasonic backward radiation was investigated to develop the nondestructive technique for interfacial roughness evaluation. 相似文献
993.
Arvind Kumar Michael A. Invernale Sung‐Yeon Jang Gregory A. Sotzing 《Journal of polymer science. Part A, Polymer chemistry》2010,48(4):756-763
Herein, we report the synthesis of conducting poly (terthiophene)s using a side chain precursor polymer approach. Random copolymers were prepared by ring opening metathesis polymerization of two norbornylene monomers, one containing a pendant terthiophene group and the other containing a pendant acetate group. Solid‐state oxidative conversion of the terthiophene units was used to produce conductive polymers. Oxidative solid‐state conversion was successful for copolymers containing as little as 1 mol % of terthiophene comonomer. The electrical and optical properties of CPs were studied as a function of the amount of electroactive moiety, terthiophene (3T), present in the copolymer. The CPs were found to have conductivity varying between 10?1 and 10?4 S/cm depending on the precursor copolymer compositions. The CPs obtained from all precursors had no significant difference in their energy gaps and showed blue to orange color transitions when switching from the oxidized to the neutral states, respectively. The absorbance intensity at 426 nm for poly(3T) from the precursors fits the Beer–Lambert law corresponding to the range of initial 3T content in the precursor copolymer composition (from 1 to 100 mol %). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 756–763, 2010 相似文献
994.
Flavonoid profiles of immature and mature fruit tissues of Citrus grandis Osbeck (Dangyuja) and overall contribution to the antioxidant effect
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995.
Chen Hui-Ming Huang Chien-Ming Chen Li-Chai Yang Chang-Syun Chang Tsung-Hsien Chen Chun-Lin Sung Ping-Jyun Kuo Wen-Lung Cheng Ming-Jen Hsiao Jen-Wen Chen Jih-Jung 《Chemistry of Natural Compounds》2022,58(3):496-500
Chemistry of Natural Compounds - A new triterpenoid, methyl 2α-(4-hydroxybenzoyl)oxy-3β-hydroxy-urs-12-en-28-oate (1), has been isolated from the leaves of Eriobotrya deflexa f. deflexa,... 相似文献
996.
Pei‐Cheng Hsu Yu‐Sheng Chen Yeukuang Hwu J. H. Je G. Margaritondo Eng Soon Tok 《Journal of synchrotron radiation》2015,22(6):1524-1527
X‐ray irradiation is shown to trigger the deposition of Cu from solution, at room temperature, on a wide variety of insulating substrates: glass, passivated Si, TiN/Ti/SiO2/Si and photoresists like PMMA and SU‐8. The process is suitable for patterning and the products can be used as seeds for electroplating of thicker overlayers. 相似文献
997.
Sung Ho Yang Jinsu Choi L. Palanikumar Eun Seong Choi Juno Lee Juan Kim Insung S. Choi Ja-Hyoung Ryu 《Chemical science》2015,6(8):4698-4703
Formation of both mechanically durable and programmably degradable layer-by-layer (LbL) films in a biocompatible fashion has potential applications in cell therapy, tissue engineering, and drug-delivery systems, where the films are interfaced with living cells. In this work, we developed a simple but versatile method for generating in situ cross-linked and responsively degradable LbL films, based on the thiol–exchange reaction, under highly cytocompatible conditions (aqueous solution at pH 7.4 and room temperature). The cytocompatibility of the processes was confirmed by coating individual yeast cells with the cross-linked LbL films and breaking the films on demand, while maintaining the cell viability. In addition, the processes were applied to the controlled release of an anticancer drug in the HeLa cells. 相似文献
998.
A large eddy simulation (LES) is performed for turbulent flow around a bluff body inside a sudden expansion cylinder chamber,
a configuration which resembles a premixed gas turbine combustor. To promote turbulent mixing and to accommodate flame stability,
a flame holder is installed inside the combustion chamber. The Smagorinsky model and the Lagrangian dynamic subgrid-scale
model are employed and tested. The calculated Reynolds number is 5,000 based on the bulk velocity and the diameter of inlet
pipe. The simulation code is constructed by using a general coordinate system based on the physical contravariant velocity
components. The predicted turbulent statistics are evaluated by comparing with the laser-doppler velocimetry (LDV) measurement
data. The agreement of LES with the experimental data is shown to be satisfactory. Emphasis is placed on the time-dependent
evolutions of turbulent vortical structures behind the flame holder. The numerical flow visualizations depict the behavior
of large-scale vortices. The turbulent behavior behind the flame holder is analyzed by visualizing the sectional views of
vortical structure.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
999.
In this paper we introduce the notion of TN-groupoids in an arbitrary groupoid, and discuss some properties in Bin(X), and obtain several results related with non-negativity of norms. 相似文献
1000.
A series of nickel(II) complexes having the (Me-Tp)2PMA ligand ((Me-Tp)2PMA = bis(5-methyl-2-thiophenemethyl)(2-pyridylmethyl)amine) with nitrates (1), chlorides (2), and perchlorates (3) as anions were synthesized and isolated. All these complexes were successfully characterized by physicochemical methods including X-ray crystallographic analysis. In complex 1, the ligand binds in a bidentate N2 fashion, whereas in the cases of 2 and 3 the ligand binds in the tridentate N2S form. The coordination geometry around the nickel(II) atoms in these complexes is distorted octahedral. 相似文献